Grinder attachment for spark testing



088. 4, 1948; J, G. C'OOPER 2,483,882

GRINDER ATTACHMENT FOR SPARK TESTING Filed Feb. 14, 1947 FIBL 2/Patented Oct. 4, 1949 483,882 H H r z 1 i-eamnamnmmvmm FOR srARK ,mnsrme1 '7 Joseph G. Cooper, Duquesne, fav assignorto "Car v ,negie-IllinoisSteel Corporation, a-egi poration 6f New-Jersey f assiieaatasaany14,19n,seaisti'vzsgny thereof, more readily visible to theworkmanmaka ing, the test. The above iafid' other relatedfe'atures ofthe inventiontv'i'li be more fully apparent from the consideration ofthe following detailed disclosure, the accompanying drawings and theappended claims:

In the drawings:

Figure 1 is a horizontal section through the attachment showing the samedetachably secured to a known type of grinding motor having aconventional grinding wheel driven thereby.

Figure 2 is a section on line II-II of Figure 1.

Figure 3 is a section on line IlI--III of Figure 1.

Figure 4 is a section on line IV-IV of Figure 3.

Referring more particularly to the drawings, represents a conventionaltype grinding motor having handle l2 which the operator grasps whenmaking a spark test. The motor drives a grinding wheel M which isadapted to make contact with a metallic workpiece l6 which may be heldin a vise or any suitable clamp, one end of the workpiece being adaptedto extend through the open end H! of the casing 20. The interior surface22 of the casing 20 is preferably painted or otherwise provided with adark opaque background so that the somewhat conical body of sparksdriven off from the work will vividly stand out in contrast to the darkbackground.

Secured to the exterior of the casing there is a band 24 riveted orotherwise secured to the casing and carrying a suitable lateral lug towhich is secured a split clamp member 26 which is provided with a wingedclamp nut 28 adapted to removably and adjustably secure the attachmentas a whole to the hub 30 of the grinding motor casing. To the exteriorof the attachment 20 there is secured a flanged member 32 which may bearon a suitable supporting stand and the casing is also equipped with ahandle 34 to facilitate manual adjustment of the position of theattachment as a whole. Secured to the casing there is a hood portion 36,the interior of which communicates by way of opening 38 with theinterior of the conelike portion of the casing 20. The front of the hoodnearest the operator is usually open, the part as indicated at 38, so asto permit the operator to have a clear view of the luminosity, shape of2 claims; (01. sr-atm' the trajectory of the sparks and other character;istics. v A conelike body of sparks being 'indicated at M) in thedrawingsas traversinga trajectory, dsually 'assunfed; for example, foilow carbon steel: The open end of] the hood t5 facing the workman orobserver, in js'om'i. cases will be closed we tran'sparent'wi dow oglassjor plastic so as "to protect the workman against the hazard offiyihg 'spark s. t v 4 Inthe n rmalopiertion v atqrwm in'sf'ert are; 'pl151 t'o'the been eridof theme-fig znariu'win the grinding wheel M toimpinge upon the upper surface of the workpiece. This will throw off ashower of sparks. Experienced operators can determine thecharacteristics of the steel by the luminosity of the sparks, the shape'of the individual particles thereof and by observation of the path ortrajectory of the individual sparks. The described device has beendetermined in practice to be advantageous since it confines the sparksand provides a contrasting background to better enable the testingWorkman to observe the characteristics of the sparks and the trajectorythereof, and it also protects the operator from the hazard of flyingsparks.

The volume or plume of sparks thrown off from the periphery of thegrinding wheel is substantially or approximately conical in shape andthe casing or shield illustrated is so shaped, constructed and arrangedas to accommodate the plume-like mass of sparks without substantialinterference. The darkened or opaque background against which the sparksare to be observed may be said to extend substantially parallel to theplane of the trajectory of the sparks. The casing, it will beunderstood, acts as a frontal shield to exclude light and also serves toprevent distortion of the plume of sparks by'the action of wind. Whilethe substantially conical portion of the casing shown and described isopen at both ends, at its smallest end it is partially filled by thegrinding wheel and its mounting. However, if desired, one or both endscould be closed. The angle or direction of the 10ngitudinal axis of thecone-like casing with relation to the plane of rotation of the grindingwheel may be said to be straight away or substantially tangent to theperiphery of the wheel so as to preclude the likelihood of the plume ofsparks impinging on the casing at any point thereof.

While I have described quite specifically the details of theconstruction and arrangement of the particular device hereinillustrated, it is to he day e,"ti1eoper named open end and to producesparks from such contact, said casing extendingin a direction generallytangential from the point of contact of the workpiece with the grindingwheel,

and a hood projecting fromsaid casing on the. ,7 side opposite theregion of contact between the grinding wheel and the workpiece in the,trajectory of sparks thrown from the workpiece, said hood having awindow through which such sparks are visible. v

2. An apparatus for spark testing comprising in combination a motorcarrying a grinding wheel, and an'elongated hollow casing carryingclamping means for detachably securing it to the motor, the casing beingopen at both ends, the end adjacent the motor being open to facilitatethe entrance of a workpiece therein for coa-ction with thegrindingwheel, the open end of said casing adjacent the motor beingadapted to enclose the section of the workpiece in contact with saidgrinding wheel, said casing extending in a direction generallytangential from the point of contact of the workpiece with the grindinwheel and having a hooded portion with an opening therein to permitobservation of the sparks given ofi as a result of the contact of thegrinding. Wheel. with theworkpiece, said casing and hooded portion beingcharacterized by the provision of a dark background to contrast withluminous sparks emanating from the workpiece, the opening in said hoodedportion being closed by a transparentwindow to shield the operator fromthe hazard of flying sparks.

d 5, JOSEPH G. COOPER. f njnpnnnncns CITED The following. references areof record in the file of this patentf UNITED STATES PATENTS 1,027,548Kohlmyer; May 28, 1912, 1,255,040 Qusley ,Jan. 29, 1918 1,797,261 HallamMar-.24, 1931 2,100,344 Medart Nov. 30, 1937 E GN PA E 4 Number Country7 Date

